<!DOCTYPE html>
<html style="height: 100%" lang="zh" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="utf-8">
<title>Line Chart</title>

<link th:href="@{/css/Chart.min.css?v=20210131}" rel="stylesheet"/>

<!-- 引入jquery -->
<script type="text/javascript" th:src="@{/ajax/libs/jquery/3.5.0/dist/jquery.min.js}"></script>
<!-- 引入 charts.js -->
<script type="text/javascript" th:src="@{/ajax/plugins/moment.min.js}"></script>
<script type="text/javascript" th:src="@{/ajax/libs/charts/2.9.4/dist/Chart.bundle.min.js}"></script>
<script type="text/javascript" th:src="@{/ajax/libs/charts/2.9.4/dist/utils.js}"></script>

<style>
canvas {
	-moz-user-select: none;
	-webkit-user-select: none;
	-ms-user-select: none;
}
</style>
</head>

<body>
	<div style="width: 75%;">
		<canvas id="canvas"></canvas>
	</div>
	<br>
	<br>
	<button id="randomizeData">Randomize Data</button>
	<button id="addDataset">Add Dataset</button>
	<button id="removeDataset">Remove Dataset</button>
	<button id="addData">Add Data</button>
	<button id="removeData">Remove Data</button>
	<script>
		var MONTHS = [ 'January', 'February', 'March', 'April', 'May', 'June',
				'July', 'August', 'September', 'October', 'November',
				'December' ];
		var config = {
			type : 'line',
			data : {
				labels : [ 'January', 'February', 'March', 'April', 'May',
						'June', 'July' ],
				datasets : [
						{
							label : 'My First dataset',
							backgroundColor : window.chartColors.red,
							borderColor : window.chartColors.red,
							data : [ randomScalingFactor(),
									randomScalingFactor(),
									randomScalingFactor(),
									randomScalingFactor(),
									randomScalingFactor(),
									randomScalingFactor(),
									randomScalingFactor() ],
							fill : false,
						},
						{
							label : 'My Second dataset',
							fill : false,
							backgroundColor : window.chartColors.blue,
							borderColor : window.chartColors.blue,
							data : [ randomScalingFactor(),
									randomScalingFactor(),
									randomScalingFactor(),
									randomScalingFactor(),
									randomScalingFactor(),
									randomScalingFactor(),
									randomScalingFactor() ],
						} ]
			},
			options : {
				responsive : true,
				plugins : {
					title : {
						display : true,
						text : 'Chart.js Line Chart'
					},
					tooltip : {
						mode : 'index',
						intersect : false,
					}
				},
				hover : {
					mode : 'nearest',
					intersect : true
				},
				scales : {
					x : {
						display : true,
						scaleLabel : {
							display : true,
							labelString : 'Month'
						}
					},
					y : {
						display : true,
						scaleLabel : {
							display : true,
							labelString : 'Value'
						}
					}
				}
			}
		};

		window.onload = function() {
			var ctx = document.getElementById('canvas').getContext('2d');
			window.myLine = new Chart(ctx, config);
		};

		document.getElementById('randomizeData').addEventListener('click',
				function() {
					config.data.datasets.forEach(function(dataset) {
						dataset.data = dataset.data.map(function() {
							return randomScalingFactor();
						});

					});

					window.myLine.update();
				});

		var colorNames = Object.keys(window.chartColors);
		document
				.getElementById('addDataset')
				.addEventListener(
						'click',
						function() {
							var colorName = colorNames[config.data.datasets.length
									% colorNames.length];
							var newColor = window.chartColors[colorName];
							var newDataset = {
								label : 'Dataset '
										+ config.data.datasets.length,
								backgroundColor : newColor,
								borderColor : newColor,
								data : [],
								fill : false
							};

							for (var index = 0; index < config.data.labels.length; ++index) {
								newDataset.data.push(randomScalingFactor());
							}

							config.data.datasets.push(newDataset);
							window.myLine.update();
						});

		document.getElementById('addData').addEventListener(
				'click',
				function() {
					if (config.data.datasets.length > 0) {
						var month = MONTHS[config.data.labels.length
								% MONTHS.length];
						config.data.labels.push(month);

						config.data.datasets.forEach(function(dataset) {
							dataset.data.push(randomScalingFactor());
						});

						window.myLine.update();
					}
				});

		document.getElementById('removeDataset').addEventListener('click',
				function() {
					config.data.datasets.splice(0, 1);
					window.myLine.update();
				});

		document.getElementById('removeData').addEventListener('click',
				function() {
					config.data.labels.splice(-1, 1); // remove the label first

					config.data.datasets.forEach(function(dataset) {
						dataset.data.pop();
					});

					window.myLine.update();
				});
	</script>
</body>

</html>
